Hi, I'm new to COD Zombies and I need some tips.

So I just started playing BO Zombies mode and it turns out that it's bit hard for me. Right now I want to get at least to 25 waves but I kept dying on 6 wave. I know about ways to get more points but I need to master leading zombies. No matter how I direct my playthrough, even if I'm trying to get my way to switch power so I can buy more guns and boosts. I have big experience with zombie games, such as Killing Floor or L4D. I would appreciate any help from y'all, I find zombie mode in this game very interesting and it's specific because of it's difficult.